Fuel additive comprising an alkyl halide

ABSTRACT

A method including using an alkyl halide, such as but not limited to, tetrabromoethane, as a fuel additive to a fuel to increase completeness of combustion of the fuel.

FIELD OF THE INVENTION

The present invention relates generally to fuel additives and methodtherefor.

BACKGROUND OF THE INVENTION

Methods and systems for marking liquid hydrocarbons or fuels are knownin the art. The fuel is generally marked by a substance that can bedetected, thereby identifying the source of the fuel. For example, asimple dyeing substance may be mixed with the fuel, thereby changing thecolor of the fuel and allowing the fuel to be identified according tothe marked color. Alternatively, the marking substance can emit light atan invisible wavelength, wherein the fuel is identified by measuring theemitted wavelength by an optical detector. According to other methods,the fuel is marked with an organic compound whose presence is laterdetected by a spectrometer.

One example of fuel marking systems is described in PCT published patentapplication WO 02/098199 (PCT application PCT/IL02/00431).

SUMMARY OF THE INVENTION

The present invention seeks to provide a novel fuel additive, as isdescribed more in detail hereinbelow.

The inventors have surprisingly found a new property for a substancethat had been previously used simply to mark fuels, as in PCT publishedpatent application WO 02/098199. For example, tetrabromoethane (TBE) hasbeen added to petroleum-based fuels, such as gasoline or diesel fuel,for the purposes of marking the fuel as an anti-theft procedure. Theinventors have now found that TBE (and other substances) may be used asa fuel additive to improve combustion characteristics, as is describedmore in detail hereinbelow.

DETAILED DESCRIPTION OF EMBODIMENTS

The fuel additive of the present invention may be added in small amountsto fuel, such as but not limited to, 1-10 ppm. This small amount doesnot affect the color or operative properties of the fuel.

Throughout the specification and claims, the term “fuel” refers to anyliquid hydrocarbon, including but not limited to, petroleum productseither refined or unrefined, such as crude oil, naphtha, gasoline,diesel fuel, jet fuel, kerosene, propane, lubricant (e. g., engine oil),hydraulic fluid, natural gas (either in gaseous or liquefied form), andthe like.

The fuel additive of the present invention is stable, miscible in andcompatible with the fuel. For example, the fuel additive may comprise ahalogenic compound, such as an alkyl halide having the general formulaC_(n)H_(2n+2−m)X_(m), where n=1,2,3 . . . , m=1,2,3 . . . X is a halogensuch as fluorine (F), chlorine (Cl), bromine (Br), and iodine (I). Anexample of such an alkyl halide is tetrabromoethane (TBE) (C₂H₂Br₄).

Other examples of alkyl halides, which may be used to carry out theinvention include but are not limited to: 1,1,2,2 tetrachloroethane(C₂H₂Cl₄), 1,1,2 trichloroethane (C₂H₃Cl₃), pentachloroethane (C₂HCl₅),hexachloroethane (C₂Cl₆), 1,2,4 trichloro cyclohexane (C₆H₉Cl₃), 1,2,4,5tetrachloro cyclohexane (C₆H₈Cl₄), ethyliodide (C₂H₅I), ethylbromide(C₂H₅Br), dichloro 1,2 dibromoethane (C₂H₂Cl₂Br₂),dichlorotribromoethane (C₂HCl₂Br₃), difluoro 1 chloroethane (C₂H₃F₂Cl),difluoro 1,2 dibromoethane (C₂H₂F₂Br₂), trifluor 1,2,2 dibromoethane(C₂HF₃Br₂), tribromopropane (C₃H₅Br₃), dibromocyclohexane (C₆H₁₀Br₂),dibromoethane (C₂H₄Br₄), n-propylbromide (C₃H₇Br), 1-bromo, 4-fluorocyclohexane (C₆H₁₀FBr), butylbromide (C₄H₉Br) and octylbromide(C₈H₁₇Br).

The fuel additive of the present invention is preferably immiscible inwater. One of the advantages of this property is that sometimes there isa water phase in fuels or in storage tanks, and the insolubility of thefuel additive in water means that the fuel additive remains in solutionwith the fuel and is not lost to the water phase.

The fuel additive of the present invention may create a large amount offree radicals. Free radicals lead to a smoother and more uniformtemperature gradient and more complete combustion in the combustionchamber. In this manner, the fuel additive improves fuel consumption.

In addition, the fuel additive of the present invention may trap heavymetal ions present in petroleum-based fuels. The trapped heavy metalions then exit with the exhaust, instead of accumulating on the innerwalls and surfaces of the combustion chamber. Thus the fuel additive hasthe synergistic effect of not only improving fuel consumption but alsocausing the combustion chamber to be cleaner, which in turn furtherimproves fuel consumption.

It is noted that the present invention is not bound or limited in anyway to the above postulations of free radicals and trapping heavy metalions. They are presented merely as a possible way of understanding howthe fuel additive of the present invention improves performance of aninternal combustion engine.

It will be appreciated by persons skilled in the art that the presentinvention is not limited by what has been particularly shown anddescribed hereinabove. Rather the scope of the present inventionincludes both combinations and subcombinations of the features describedhereinabove as well as modifications and variations thereof which wouldoccur to a person of skill in the art upon reading the foregoingdescription and which are not in the prior art.

1. A method comprising: using an alkyl halide as a fuel additive to afuel to increase completeness of combustion of the fuel.
 2. The methodaccording to claim 1, further comprising using the alkyl halide toincrease cleanliness of a combustion chamber in which the fuel undergoescombustion.
 3. The method according to claim 1, wherein said alkylhalide comprises tetrabromoethane.
 4. The method according to claim 1,wherein said alkyl halide comprises at least one of tetrabromoethane(C₂H₂Br₄), 1,1,2,2 tetrachloroethane (C₂H₂Cl₄), 1,1,2 trichloroethane(C₂H₃Cl₃), pentachloroethane (C₂HCl₅), hexachloroethane (C₂Cl₆), 1,2,4trichloro cyclohexane (C₆H₉Cl₃), 1,2,4,5 tetrachloro cyclohexane(C₆H₈Cl₄), ethyliodide (C₂H₅I), ethylbromide (C₂H₅Br), dichloro 1,2dibromoethane (C₂H₂Cl₂Br₂), dichlorotribromoethane (C₂HCl₂Br₃), difluoro1 chloroethane (C₂H₃F₂Cl), difluoro 1,2 dibromoethane (C₂H₂F₂Br₂),trifluor 1,2,2 dibromoethane (C₂HF₃Br₂), tribromopropane (C₃H₅Br₃),dibromo cyclohexane (C₆H₁₀Br₂), dibromoethane (C₂H₄Br₄), n-propylbromide(C₃H₇Br), 1-bromo, 4-fluoro cyclohexane (C₆H₁₀FBr), butylbromide(C₄H₉Br) and octylbromide (C₈H₁₇Br).